(a) Field of the Invention
This invention relates to selected 8-(substituted)-2-(4-pyridinyl)-9H-purin-6-amines, their preparation and cardiotonic use, and to intermediates therefor.
(b) Description of the Prior Art
Taylor et al [J. Am. Chem. Soc. 81, 2442-8 (1959)] show, inter alia, the preparation of 2-(3-pyridinyl)-9H-purin-6-amine by heating the nicotinamidine salt of isonitrosomalonitrile in formamide to produce 4,6-diamino-5-nitroso-2-(3-pyridinyl)pyrimidine and heating the reaction mixture containing said 5-nitroso compound and formamide with a mixture of formic acid and sodium dithionite dihydrate to produce said 2-(3-pyridinyl)-9H-purin-6-amine, for which no use is indicated.
Baddiley et al [J. Chem. Soc. 1943, pp. 386-7] show the catalytic hydrogenation of 4,6-diamino-5-phenylazopyrimidine in ethanol using Raney nickel as catalyst to produce 4,5,6-triaminopyrimidine.
Bullock et al [U.S. Pat. No. 3,041,340, issued June 26, 1962] show, inter alia, N-(4-, 3- and 2-pyridinyl)-9H-purin-6-amines as vegetable growth stimulants.